Schizophrenia (SZ) and bipolar disorder (BD) are severe and persistent debilitating psychiatric illnesses that are generally associated with considerable morbidity and extreme disability. Due to the severity of these disorders, especially the negative impact of a psychotic episode on a patient, and the diminishing recovery after each psychotic episode, there is a need to more conclusively identify individuals who have or are at risk of developing SZ or BD, for example, to confirm clinical diagnoses, to allow for prophylactic therapies, to determine appropriate therapies based on their genotypic subtype, and to provide genetic counseling for prospective parents with a history of the disorder.
Various genes and chromosomes have been implicated in etiology of SZ and BD. For example, whole genome scans for genes involved in SZ and BD have implicated chromosome 2 (see, e.g., Williams et al., Hum. Mol. Genet. 8:1729-1739 (1999); Middleton et al., Am. J. Hum. Genet. 74:886-897 (2004); Bennett et al., Mol. Psychiatry 7:189-200 (2002)).
Similarly, whole genome scans for genes involved in SZ and BD have implicated chromosome 5, but these linkage scans have generally been too low in resolution to identify specific genes (see, e.g., Park et al., Mol. Psychiatry 9:1091-1099 (2004); Kendler et al., Am. J. Psychiatry 157:402-408 (2000); Straub et al., Mol. Psychiatry 7:542-559 (2002); Devlin et al., Mol. Psychiatry 7:689-694 (2002); Lewis et al., Am. J. Hum. Genet. 73:34-48 (2003); Hong et al., Am. J. Med. Genet. B Neuropsychiatr. Genet. 125:83-86 (2004); Marcheco-Teruel et al., Am. J. Med. Genet. B Neuropsychiatr. Genet. 141:833-843 (2006); Shink et al., Prog. Neuropsychopharmacol. Biol. Psychiatry 26:1273-1277 (2002).